Abstract
Ecoroofs, also known as green roofs, are becoming widely installed with relatively little data collected on their in situ performance. For this study, three large ecoroof portions (280–500 m2) located on two different buildings in Portland, OR, USA were instrumented and monitored continuously for more almost 3 years. For the Broadway Building, a student dormitory on the campus of Portland State University, measurement of ecoroof energy conservation and rainwater discharge abatement helped qualify the building for its Leadership in Energy and Environmental Design silver award. Using an electromagnetic flowmeter, stormwater discharge was monitored and compared to rainfall. Over a 3-year period, rainwater discharge was reduced by about 25%. Rooftop heat flux was simultaneously measured using an array of temperature sensors. When compared to a rock ballast roof exposed to the same weather conditions, the ecoroof heat flux was reduced by 13% in winter and 72% in summer. Retrofit ecoroof installations on the Multnomah County Building, an office building, were also monitored for almost 3 years for two separate ecoroof sections with different plantings, using similar electromagnetic flow meters and a rain gauge. Overall reductions of rainwater discharge were 12% and 17% for those two ecoroofs. For all three ecoroofs, discharge reductions varied widely by month due to seasonal differences in the amount of rainfall. Based on the measurements taken in this study, ecoroofs in Portland, OR, USA appear to offer some performance advantages.
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References
Barrio EPD (1998) Analysis of green roofs cooling potential in buildings. Energy build 27:179–193
Bengtsson L (2005) Hydrological function of a thin extensive green roof in Southern Sweden. Nord hydrol 36(3):259–268
Graham P, Kim M (2003) Evaluating the stormwater management benefits of green roofs through water balance modeling. In Proc. of 1st North American Green Roof Conference: Greening Rooftops for Sustainable Communities, Chicago. Cardinal Group, Toronto
Hunt B, Moran A, Jennings G (2004) North Carolina green roof stormwater quantity and quality field evaluation. In Proc. of 2nd North American Green Roof Conference: Greening Rooftops for Sustainable Communities, Portland, OR, USA. Cardinal Group, Toronto
Hutchinson D, Abrams P, Retzlaff R, Liptan T (2003) Stormwater monitoring two ecoroofs Portland, Oregon, USA. In Proc. of 1st North American Green Roof Conference: Greening Rooftops for Sustainable Communities, Chicago. Cardinal Group, Toronto
Johnston C, McCreary K, Nelms C (2004) Vancouver Public Library green roof monitoring project. In Proc. of 2nd North American Green Roof Conference: Greening Rooftops for Sustainable Communities, Portland. Cardinal Group, Toronto
Liu K, Baskaran B (2003) Thermal performance of green roofs through field evaluation. In Proc. of 1st North American Green Roof Conference: Greening Rooftops for Sustainable Communities, Chicago. Cardinal Group, Toronto
Liu K, Minor J (2005) Performance evaluation of an extensive green roof. National Research Council of Canada, Ottawa, NRCC-48204
MacMillan G (2004) York University rooftop garden stormwater quantity and quality performance monitoring report. In Proc. of 2nd North American Green Roof Conference: Greening Rooftops for Sustainable Communities, Portland. Cardinal Group, Toronto
Mentens J, Raes D, Hermy M (2006) Green roofs as a tool for solving the rainwater runoff problem in the urbanized 21st century. Landsc Urban Plan 77(33):217–226, Elsevier Science
Moran A, Hunt B, Smith J (2005) Hydrologic and water quality performance from greenroofs in Goldsboro and Raleigh, North Carolina. In Proc. of 3rd North American Green Roof Conference: Greening Rooftops for Sustainable Communities, Washington, D.C. Cardinal Group, Toronto
Niachou A, Papakonstantinou K, Santamouris M, Tsangrassoulis A, Mihalakakou G (2001) Analysis of the green roof thermal properties and investigation of its energy performance. Energy build 33(7):719–729
Onmura S, Matsumoto M, Hokoi S (2001) Study on evaporative cooling effect of roof lawn gardens. Energy build 33(7):653–666
Rowe DB, Rugh CL, VanWoert N, Monterusso MA, Russell DK (2003) Green roof slope, substrate depth, and vegetation influence runoff. In Proc. of 1st North American Green Roof Conference: Greening Rooftops for Sustainable Communities, Chicago. Cardinal Group, Toronto
Sonne J (2006) Evaluating green roof energy performance. ASHRAE J 48(2):59–61
Takakura T, Kitade S, Goto E (2000) Cooling effect of greenery cover over a building. Energy build 31(1):1–6
Tan PY, Wong NH, Chen Y, Ong CL, Sia A (2003) Thermal benefits of rooftop gardens in Singapore. In Proc. of 1st North American Green Roof Conference: Greening Rooftops For Sustainable Communities, Chicago. Cardinal Group, Toronto
Van Seters T, Rocha L (2007) Evaluating the runoff quantity and quality performance of an extensive green roof in Toronto, Ontario. In Proc. of 5th North American Green Roof Conference: Greening Rooftops For Sustainable Communities, Minneapolis. Cardinal Group, Toronto
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Spolek, G. Performance monitoring of three ecoroofs in Portland, Oregon. Urban Ecosyst 11, 349–359 (2008). https://doi.org/10.1007/s11252-008-0061-z
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DOI: https://doi.org/10.1007/s11252-008-0061-z